1. Field of the Invention
The present invention relates to a travelling field machine. In particular, the invention relates to a travelling field machine with a stator and a rotor, each of which comprising at least one stator coil or one rotor coil, respectively, with the stator or the rotor, respectively, comprising a soft magnetic iron body with a stator or rotor back, respectively, at which spaced grooves are formed under the forming of teeth.
2. Definition of Terms
The term “travelling field machines”, i. e. asynchronous, synchronous, reluctance machines, permanently excited electrical machines, etc. covers motors as well as generators, whereby it is of no significance in particular for the invention whether such a machine is designed as a rotating machine or, for example, as a linear motor. Moreover, the invention may be applied both to internal rotor machines and external rotor machines.
In the reduction of the volume of highly efficient electrical machines the form of construction and the arrangement of the conductors of the field windings play a decisive role. Conductors with a minimum length in the winding overhangs at a high utilisation of the space reduce the ohmic losses and increase the power density.
Due to the fact that the ohmic losses in the control circuit and in the (stator) winding are proportional to the current to be connected, a certain conductor length has to be provided in the magnetic field in order to generate an induced back voltage corresponding to the desired high control voltage in a conductor arrangement of a resistance as low as possible.
Conventional electrical machines in their majority are wound with continuous wires—mostly with round cross-section. Though a thin flexible wire may easily be placed into the grooves, it has the disadvantage of a poor space utilisation in the grooves and winding overhangs. Wires with round cross-section cannot fully utilise the cross-sectional area of the groove. The space in the winding overhangs is thus also utilised only inadequately, and the magnetically ineffective conductor length, the overall weight, the required space, and the ohmic losses increase.